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Biomedical subjects

Y Moens

Publications and source records attributed to Y Moens.

At least 19 recordsLinked to original sources
PubMed1998

Inhalation anaesthesia for the castration of piglets: CO2 compared to halothane.

General anaesthesia with 80% CO2/20% O2 and 5% halothane in O2 (mask induction) was compared for castration of 3-4 week-old piglets. One group was castrated without anaesthesia. Of the noncastrated control groups one had CO2- and one halothane anaesthesia, one breathed room air through the induction system, and one was held in castration position. The behaviour to induction and castration was assessed, and the cortisol-, ACTH- and beta-endorphin plasma concentrations were determined to quantify the stress elicited by anaesthesia, castration and handling. Violent struggling and vocalization were elicited by CO2 and positioning into the mask induction system while breathing room air; halothane induction was quiet. CO2 induced profound surgical anaesthesia; whereas under halothane anaesthesia some animals exhibited still a slight reaction to castration. Recovery was fast, smooth and quite. Permanent violent struggling and vocalization were elicited by castration without anaesthesia. Plasma cortisol was not a sensitive tool to judge castration stress. The high ACTH and beta-endorphin plasma concentrations elicited by CO2 anaesthesia confirm our clinical experience. General anaesthesia is fast and safely induced with CO2 in piglets and castration can be performed without any reaction, but with CO2 anaesthesia the stress is not reduced.

Anesthesia, Inhalation↗
PubMed1998

Influence of tidal volume and positive end-expiratory pressure on inspiratory gas distribution and gas exchange during mechanical ventilation in horses positioned in lateral recumbency.

OBJECTIVE: To study effects of intermittent positive-pressure ventilation (IPPV) with large tidal volumes and addition of positive end-expiratory pressure (PEEP) on maldistribution of ventilation in anesthetized horses positioned in lateral recumbency. ANIMALS: 6 healthy adult horses. PROCEDURE: Anesthesia was induced by i.v. infusion of thiopental sodium and guiafenesin and was maintained with supplemental doses of thiopental and i.v. infusion of chloral hydrate. Functional separation of the lungs was achieved, using a tube-in-tube intubation technique. Intermittent positive-pressure ventilation of both lungs with air was done by use of an anesthetic circle system and a ventilator. Data were collected during spontaneous respiration and during IPPV, using increasing tidal volumes with and without PEEP of 10 and 20 cm of H2O. RESULTS: Uneven distribution of inspired gas between the lungs that existed during spontaneous respiration was not altered by IPPV and large tidal volumes. Addition of PEEP caused a significant and reversible shift of inspired gas to the dependent lung and preferentially increased functional residual capacity of the nondependent lung. This was accompanied by significant increase in PaO2. With IPPV, the combined effects of PEEP and large tidal volume caused an increase of the fractional distribution of inspired gas to the dependent lung from 34% to 50%, accompanied by an increase in PaO2 and alveolar dead space of both lungs. CONCLUSIONS AND CLINICAL RELEVANCE: Use of PEEP during IPPV changes distribution of inspired gas. Increased in PaO2 can be attributed to improved ventilation-perfusion, especially in the dependent lung, in which previously collapsed lung units might have been reopened and participated again in gas exchange after redistribution of inspired gas. The most pronounced effects of IPPV and PEEP were associated with high airway pressures, which are likely to offset the beneficial effects of the increase of PaO2 on total oxygen availability to the tissues because of the expected negative effects on cardiac output.

Anesthesia, General↗
PubMed1997

Ultrasound spirometry in the horse: a preliminary report on the method and the effects of xylazine and lobeline hydrochloride medication.

A new computerised ultrasound-based spirometry system according to Buess et al. (1995) modified by a double flow measurement facility was used to study pulmonary function in healthy horses and horses affected with subclinical and manifest chronic bronchiolitis (CB). The horses were first evaluated at rest without any medication. On another occasion all horses were tested following i.v. administration of xylazine (0.4 mg/kg) and following i.v. administration of lobeline hydrochloride (l.hy.; 0.2 mg/kg) to evaluate the effect of xylazine and l.hy. on different spirometric variables. Ultrasound-based spirometry proved to be an easily applicable method for lung function testing, even in difficult horses. However, there existed a pronounced physiological variation for all measured lung function parameters and no significant differences between healthy horses and horses with chronic bronchiolitis could be found except for the expiratory tidal volume (VTE p < 0.05). Individually, a marked decrease of variability from breath to breath following either xylazine and l.hy. administration could be observed for all parameters, except the flow-time-ratio (Tpef./ Texp.) and the flow-volume-ratio (Vpef./Vexp).

Animals↗
PubMed1995

Distribution of inspired gas to each lung in the anaesthetised horse and influence of body shape.

The distribution of inspired gas to each lung, time constants of the lungs and parameters of gas exchange were studied in 2 groups of horses (mean bwt 606 kg), anaesthetised using thiopentone and chloral hydrate and breathing room air. One group (n = 4) had a downward curved abdominal contour (round-bellied) and the other group (n = 4) had an upward curved abdominal contour (flat-bellied). An equal distribution of inspired gas between the lungs existed in both groups in dorsal recumbency. Flat-bellied horses maintained this equal distribution in lateral recumbency whereas in round-bellied horses an uneven distribution of tidal volume (VT) developed. The percentage of (VT) distributed to the dependent lung was 23% and 38% for left and right lateral recumbency respectively. The distribution of VT agreed with the ratio of time constants of the lungs in flat-bellied horses but differed markedly from this ratio in round-bellied horses suggesting that, in the latter, factors other than compliance and resistance play a role in distribution of ventilation. Round-bellied horses had a lower PaO2 and a larger (A-a)PaO2 than flat-bellied horses in all body positions. The results are compatible with the known hypothesis that pressure exerted by abdominal contents on the dependent lung and diaphragm is an important factor in ventilation/perfusion mismatch of the anaesthetised horse.

Anesthesia↗
PubMed1994

Differential artificial ventilation in anesthetized horses positioned in lateral recumbency.

Effects of differential ventilation on gas exchange were studied in 7 isoflurane-anesthetized, laterally recumbent horses, and were compared with effects of conventional ventilation, using similar minute volume. A tracheal tube-in-tube intubation technique allowed each lung to be connected separately to an anesthetic circle system with a ventilator. Two distribution patterns of tidal volume were investigated; half the tidal volume was distributed to each lung and two-thirds the tidal volume was distributed to the dependent lung. Effects of the combination of these patterns with positive end-expiratory pressure (PEEP) of 10 and 20 cm of H2O to the dependent lung were investigated. Differential ventilation maintained PaCO2, but significantly increased PaO2 from 180 to 270 mm of Hg (+44%) and decreased shunt perfusion from 22 to 19% (-15%), regardless of the distribution pattern used. Mean airway pressure was lower than the value detected during conventional ventilation. The combination of differential ventilation with selective PEEP was followed by a decrease in PaCO2 and further increase of PaO2 and decrease of shunt, which were similar for both distribution patterns. Effects of PEEP of 20 cm of H2O were more pronounced than those of PEEP of 10 cm of H2O. Owing to the combined effects of differential ventilation and selective PEEP, PaO2 increased to 399 mm of Hg and shunt decreased to 15%. This represents increase of 112% and decrease of 33% respectively, compared with values for conventional ventilation. Mean airway pressure increased maximally to 23 cm of H2O, which was 11 cm of H2O greater than the value for conventional ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, General↗
PubMed1992

A tracheal tube-in-tube technique for functional separation of the lungs in the horse.

The tube-in-tube technique for the functional separation of the lungs in intact anaesthetised adult horses is based on fibre-optic-guided left-sided endobronchial intubation avoiding tracheostomy. It facilitates a valid separation of the two lungs despite variability in bronchial and carinal anatomy. No clinical complications that could be related to its use have been seen.

Animals↗
PubMed1990

A comparative study of medetomidine/ketamine and xylazine/ketamine anaesthesia in dogs.

The anaesthetic and physiological effects of a combination of 40 micrograms medetomidine with 2.5 ketamine, 5.0 or 7.5 mg/kg administered intramuscularly were compared with the effects of a combination of 1 mg/kg xylazine and 15 mg/kg ketamine. All the combinations rapidly induced an anaesthetic state that permitted endotracheal intubation, with the absence of the pedal reflex and with good muscle relaxation, and induced bradycardia that was less pronounced as the dose of ketamine was increased. All the combinations produced a decrease in respiratory rate. Increasing the dose of ketamine combined with medetomidine resulted in a very significant prolongation of the duration of anaesthesia, the duration of muscle relaxation and the arousal time. The duration of the anaesthetic effects of 40 micrograms/kg medetomidine with 5 mg/kg ketamine was comparable to that provided by the recommended xylazine/ketamine combination but the period of muscle relaxation was significantly longer. The recovery from medetomidine/ketamine took longer than recovery from xylazine/ketamine but there were fewer side effects.

Analysis of Variance↗
PubMed1989

Arterial-alveolar carbon dioxide tension difference and alveolar dead space in halothane anaesthetised horses.

Arterial-alveolar carbon dioxide tension differences (a-A) PCO2 and alveolar dead space were measured during clinical halothane anaesthesia of 110 horses with the help of continuous infra-red carbon dioxide analysis of expiratory gas. Mean (a-A) PCO2 was 1.6 +/- 0.8 kPa. Alveolar dead space expressed as a percentage of alveolar tidal volume had a mean value of 23 +/- 13 per cent. Influence on (a-A) PCO2 and alveolar dead space of the following variables was tested statistically: age, weight, body position, respiration mode and duration of anaesthesia. (a-A) PCO2 was influenced positively by weight (P less than 0.0001) and adoption of dorsal recumbency (P less than 0.01). Alveolar dead space was influenced positively by weight (P less than 0.0005), adoption of dorsal recumbency (P less than 0.01), intermittent positive pressure ventilation (P less than 0.0001) and duration of anaesthesia (P less than 0.05).

Anesthesia, Inhalation↗
PubMed1981

Use of infra-red carbon dioxide analysis during general anaesthesia in the horse.

The carbon dioxide content of respiratory gases may be monitored by the use of an infra-red carbon dioxide analyser. The technique allows continuous and non-invasive recording of important information concerning the ventilatory, circulatory and metabolic states of the anaesthetised horse. Some of the monitoring capabilities of a carbon dioxide analyser (capnograph) are reviewed with illustrations from cases anaesthetised in the authors' clinic. Technical faults in the anaesthetic apparatus and the connections with the "patient" could be readily detected and emergency situations immediately recognised and treated without delay. Use of the apparatus allowed refinement of the anaesthetic technique and greatly augmented the safety of general anaesthesia.

Analgesics↗
PubMed1978

[A simple modification for the electrochemical oxygen analyzer to improve accuracy during prolonged closed system anaesthesia (author's transl)].

A simple modification of the condenser used with the electro-chemical oxygen analyzer (Dräger BioMarine OA202 R) consists of filling the distal chamber with hygroscopic silicagel. This prevents condensation of water vapour on the sensor thus allowing the accuracy during prolonged closed system anaesthesia to remain nearly unaffected (fade less than 0.5%/h).

Anesthesia, General↗